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    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
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    <title>Document</title>
</head>
<body>
    <script>
        let a1='雪碧';
        let a2='可乐'; 
        let a3='';
        // 现在需要a1是可乐，a2是雪碧；
        a3 =a1;
        a1=a2;
        a2=a3;
        console.log("a1"+a1 , "a2"+a2);
    </script>
</body>
</html>